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//
// -------------------------------------------------------------------
//
// GEANT4 Class header file
//
//
// File name:  G4ModifiedMephi
//
// Author:        V. Ivanchenko
// 
// Creation date: 27 October 2020
//
// Modifications: 
//
// Class Description: 
//
// Bremsstrahlung Angular Distribution Generation 
// A.G. Bogdanov et al., IEEE Trans. Nuc. Sci., Vol.53, No.2, 2006
//
// -------------------------------------------------------------------
//

#ifndef G4ModifiedMephi_h
#define G4ModifiedMephi_h 1

#include "G4ios.hh"
#include "globals.hh"
#include "G4VEmAngularDistribution.hh"

class G4ModifiedMephi : public G4VEmAngularDistribution
{

public:

  explicit G4ModifiedMephi(const G4String& name = "");

  ~G4ModifiedMephi() override;

  G4ThreeVector& SampleDirection(const G4DynamicParticle* dp,
                                 G4double gEnergy, G4int Z,
                                 const G4Material* mat = nullptr) final;

  void SamplePairDirections(const G4DynamicParticle* dp,
			    G4double elecKinEnergy,
                            G4double posiKinEnergy,
                            G4ThreeVector& dirElectron,
                            G4ThreeVector& dirPositron,
                            G4int Z = 0,
                            const G4Material* mat = nullptr) final;

  void PrintGeneratorInformation() const override;

  // hide assignment operator 
  G4ModifiedMephi & operator=(const  G4ModifiedMephi &right) = delete;
  G4ModifiedMephi(const  G4ModifiedMephi&) = delete;

private:

  G4double SampleCosTheta(G4double primKinEnergy, G4double gEnergy,
                          G4double mass);

};

#endif